Search Results (29)

Background/Objectives: To compare mechanical behavior, shaping performance, and safety of an original reciprocating endodontic instrument (Reciproc^® Blue) with two visually similar replicas obtained from an online marketplace. Methods: The original Reciproc^® Blue and two replica (designated Replica 1 and Replica 2) instruments purchased from AliExpress were tested. Evaluations included torque resistance, bending resistance, cyclic fatigue resistance (all according to ISO 3630-1 standards, n = 10 per group per test), and an in vitro shaping procedure using artificial root canals in plastic blocks (5 canals per instrument, n = 10 instruments per group) were carried out. Preparation time, number of pecks, procedural errors (blockages, ledges, deformations), and instrument fractures were recorded. Surface characteristics of unused (n = 2) and used instruments (n = 2) were examined using scanning electron microscopy (SEM). Statistical analysis used one-way ANOVA, Welch ANOVA, or Kruskal–Wallis tests according to the distribution and variance pattern of each endpoint, followed by the corresponding post hoc test. Repeated use was analyzed with a linear mixed effects model and checked with a robust generalized estimating equation sensitivity analysis. Deformation-free and fracture-free event curves were compared with exploratory log rank tests. Results: The original instrument showed the highest Mf/D³ and Mt/D³ values. Overall group differences were significant for Mf/D³ (Welch p < 0.001) and Mt/D³ (Welch p = 0.001), with significant Games Howell contrasts between the original and Replica 2. Replicas showed longer cyclic fatigue life (Original 407.1 s, Replica 1 490.2 s, Replica 2 607.8 s; ANOVA p < 0.001). The original instrument had a lower average preparation time for each canal than both replicas (72.8 s vs. 95.8 s and 92.3 s; Kruskal–Wallis p < 0.001) and a lower average number of pecks (8.64 vs. 9.71 and 10.00; p = 0.008). Exploratory log rank comparisons also showed group differences in the deformation-free and fracture-free event curves (Holm adjusted p = 0.005 and p = 0.024, respectively). Both replicas failed to reach working length in 4 out of 10 cases each, with high rates of blockages (Replica 1: 7/10; Replica 2: 2/10), ledges (Replica 1 only), and deformations. The limited SEM subsample revealed severe wear of cutting edges in Replica 1. Conclusions: Both tested replicas exhibited significant deviations in mechanical behavior and markedly inferior shaping safety compared to the original Reciproc^® Blue instrument, despite superficial visual similarity. Therefore, dental practitioners should be aware that low-cost imitations may compromise clinical safety. Full article

The counterfeiting of official documents and banknotes represents a critical threat to global security and requires robust and low-cost protection techniques. This work presents an innovative information security system that uses photoluminescent inks for chromatic multiplexing of QR codes. Unlike conventional cryptographic methods, the proposed approach employs physical-layer information hiding through the superposition of two QR codes encoded in magenta and cyan colors on a white background. The controlled interaction between these codes generates an additional logical state that enables a third representation of information through pixel-level operations. The resulting chromatic QR code remains visually imperceptible under ambient illumination and can be reliably recovered through chromatic demultiplexing and thresholding process. Additionally, its visibility can be enhanced under ultraviolet (UV) excitation due to photoluminescent behavior and spectral response variations. The experimental results demonstrate that both encoded data layers can be extracted independently with high fidelity using standard CMOS sensors, while preserving structural integrity and decodability. The proposed scheme increases information density within a single optical tag while improving resistance against unauthorized replication and visual forgery. Full article

Physically unclonable functions (PUFs) are critical security primitives used in authentication and cryptographic key generation. Among these, structural color-based PUFs offer distinct advantages, including fade resistance and the ability to conceal multi-dimensional information. However, current fabrication methods rely heavily on wet processes and laser ablation. Consequently, there is a significant need for flexible PUF labels capable of being produced through a facile and dry process. Here, we present stress-relief modulated photonic crystal PUF labels designed for multi-level dynamic encryption. We achieve random patterning of nanograting-based photonic crystals by leveraging curved pinning edge-induced interruptions and the uncontrolled bulking of the polymeric elastomer due to the uneven adhesion force from the tape. Using artificial intelligence-based deep learning algorithms, we authenticate the labels by extracting structural color, brightness, and saturation, which are determined by the grating periodicity, depth, and orderliness of each pixel. Furthermore, we integrated these photonic crystal patterns with dynamically modulated optical erasure to extend encryption capacity from the spatial to the temporal dimension. We anticipate this approach will enable advanced wearable anti-counterfeiting labels and multi-level digital encryption systems. Full article

Physical Unclonable Functions (PUFs) represent a highly promising hardware security primitive, yet they face constraints of insufficient reliability and threats from modeling attacks. This paper designs a novel Feed-Forward Crossbar Matrix Arbiter PUF (FC-MA PUF). It incorporates an inter-stage crossbar structure, a feed-forward control system, and a mechanism for selecting reliable challenge-response pairs. These features significantly enhance the structural non-linearity and stability, substantially improving security and adaptability to a wider range of operating environments. It provides a high-strength authentication solution with low resource overhead for lightweight security-demanding devices such as IoT devices. The proposed FC-MA PUF has been successfully implemented on a Field-Programmable Gate Array (FPGA) platform. Experimental results for the selected 4-stage FC-MA PUF configuration show a bias, inter-chip uniqueness, and bit error rate (BER) of 49.88%, 49.68%, and 0.018%, respectively. Furthermore, the structure allows for flexible configuration of the number of feed-forward modules based on practical application requirements: a greater number of feed-forward modules enhances security but also leads to an increased BER and a decreased proportion of stable challenge-response pairs. Experimental results based on a training set of 1,000,000 challenge-response pairs demonstrate that: with two feed-forward units, the stable (Challenge Response Pair)CRP ratio is 39.72% and the Covariance Matrix Adaptation Evolutionary Strategies (CMA-ES) attack prediction success rate is 58.20%; with three units, the ratio decreases to 29.12% and the prediction rate drops to 54.91%; with four units, these values further decline to 20.18% and 52.33% respectively. These results confirm that the proposed FC-MA PUF effectively resists multiple modeling attacks, including Logistic Regression (LR), Support Vector Machine (SVM), and CMA-ES. Full article

Most of the existing carbon dot (CD)-based afterglow materials are limited to a single emission mode of either room-temperature phosphorescence (RTP) or delayed fluorescence (DF), which makes it difficult to meet the application requirements of advanced anti-counterfeiting and multi-level information encryption. Therefore, the development of CD-based composite materials with multi-mode afterglow emission, long lifetime and high stability holds significant research significance and application value. In this study, long-afterglow manganese/nitrogen co-doped CDs@boric acid (BA) composites (Mn, N-CDs @BA) are successfully prepared, and their optical properties and emission mechanism are clarified. The results demonstrate that the Mn, N-CDs @BA composites exhibit wavelength-dependent dual-afterglow emission characteristics of RTP and DF. Under 254 nm ultraviolet (UV) light excitation, they exhibit DF emission with an average lifetime of 903.36 ms. Under 365 nm UV light excitation, RTP emission with an average lifetime of 354.43 ms is observed. Moreover, the afterglow color exhibits time dependence. Based on the triple emission modes (fluorescence, RTP and DF) of the Mn, N-CDs @BA composites, optical patterns were designed and fabricated, and counterfeit-resistant and unclonable anti-counterfeiting and high concealment information encryption were successfully achieved. This work develops a potentially feasible approach for next-generation advanced optical anti-counterfeiting and information encryption systems. Full article

Pharmacotherapy is a key component of obesity management, yet treatment failure remains a prevalent challenge in clinical practice. Such failure may present as insufficient pharmacological response, early discontinuation, or post-treatment weight regain, underscoring the discrepancy between clinical trial efficacy and real-world outcomes. The effectiveness of anti-obesity medications (AOMs) is influenced by psychiatric comorbidities, including depression, anxiety, and disordered eating patterns, as well as environmental and socioeconomic factors such as limited healthcare access, weight-related stigma, and high medication costs. Individual characteristics, including physical activity, body composition, visceral adiposity, and microbiome profile, further modulate treatment outcomes. Pharmacokinetic and pharmacotherapeutic limitations such as drug-phenotype mismatch, route of administration, suboptimal formulations, and exposure to counterfeit products also compromise efficacy. No less important are genetic and immunological factors, comprising pharmacogenomic variants of both incretin and melanocortin receptors along with antidrug antibodies (ADAs), which may constitute therapy resistance. Concomitant medications and comorbid endocrine disorders can additionally attenuate weight-loss effects. The objective of this review is to characterize the multifactorial nature of resistance and refractoriness to anti-obesity therapy, and the importance of identifying pretreatment predictive factors for recognizing individuals at risk of inadequate or lack of response, thereby enabling personalized management strategies and improving long-term clinical outcomes, particularly in “difficult-to-treat” patients. Full article

The escalating prevalence of counterfeiting and forgery has imposed unprecedented demands on advanced anti-counterfeiting technologies. Traditional luminescent materials, relying on single-mode or static emission, are inherently vulnerable to replication using commercially available phosphors or simple spectral blending. Multimode luminescent materials exhibiting excitation wavelength-dependent emission offer significantly higher encoding capacity and forgery resistance. Herein, we report the colloidal synthesis of lanthanide-doped Cs₂ZrCl₆ nanocrystals (Ln³⁺ = Tb, Eu, Pr, Sm, Dy, Ho) via a robust hot-injection route. These nanocrystals universally exhibit efficient host-to-guest energy transfer from self-trapped excitons (STEs) under 254 nm, yielding sharp characteristic Ln³⁺ f–f emission alongside the intrinsic broadband STE luminescence. Critically, Tb³⁺ enables direct 4f → 5d excitation at ~275 nm, while Eu³⁺ introduces a low-energy Eu³⁺ ← Cl⁻ LMCT band at ~305 nm, completely bypassing STE emission. Due to their multimode luminescent characteristics, we fabricate a triple-mode anti-counterfeiting label displaying different colors under different types of excitation. These findings establish a breakthrough excitation-encoded multimode platform, offering potential applications for next-generation photonic security labels, scintillation detectors, and solid-state lighting applications. Full article

Minimizing the spectrum overlaps of energy transfer (ET) is necessary but not sufficient for achieving high-sensitivity film thermosensing. Herein we have designed two blue emitters of DBA-BPAc and Z-DBABH exhibiting blue and bluish-green emissions, respectively, to hybridize with the red-emitting Ir(MDQ)₂(acac). Compared with Z-DBABH, DBA-BPAc shows a larger spectrum overlap of ET and a relatively smaller discrepancy in fluorescence thermal decay, while its emission spectrum displays a much smaller overlap with that of Ir(MDQ)₂(acac). The dual minimization of spectrum overlap of ET and emissions results in its superior ratiometric film thermosensing of the DBA-BPAc film in wide-range and high-temperature regions. The DBA-BPAc/Ir(MDQ)₂(acac) film exhibits a maximum relative sensitivity (S_r) of 3.36% °C⁻¹ at 166 °C, exceeding 0.43% °C⁻¹ in 50–265 °C. In comparison, the Z-DBABH/Ir(MDQ)₂(acac) system displays a reliable but relatively lower performance, with a maximum S_r of 1.92% °C⁻¹ (at 300 °C). The temperature resolution remains below 2.06 °C throughout the entire temperature range (20–300 °C), achieving a best value of 0.60 °C at 180 °C. Notably, both films display distinct naked-eye color transitions with temperature changes, enabling multi-level anti-counterfeiting applications. This work provides new insights for designing high-performance thermometers. Full article

Traditional systems in real life lack transparency and ease of use due to their reliance on centralization and large infrastructure. Furthermore, many sectors that rely on information technology face major challenges related to data integrity, trust, and counterfeiting, limiting scalability and acceptance in the community. With the decentralization and digitization of energy transactions in smart grids, security, integrity, and fraud prevention concerns have increased. The main problem addressed in this study is the lack of a secure, tamper-resistant, and decentralized mechanism to facilitate direct consumer-to-prosumer energy transactions. Thus, this is a major challenge in the smart grid. In the blockchain, current consensus algorithms may limit the scalability of smart grids, especially when depending on popular algorithms such as Proof of Work, due to their high energy consumption, which is incompatible with the characteristics of the smart grid. Meanwhile, Proof of Stake algorithms rely on energy or cryptocurrency stake ownership, which may make the smart grid environment in blockchain technology vulnerable to control by the many owning nodes, which is incompatible with the purpose and objective of this study. This study addresses these issues by proposing and implementing a hybrid framework that combines the features of private and public blockchains across three integrated layers: user interface, application, and blockchain. A key contribution of the system is the design of a novel consensus algorithm, Proof of Energy, which selects validators based on node roles and randomized assignment, rather than computational power or stake ownership. This makes it more suitable for smart grid environments. The entire framework was developed without relying on existing decentralized platforms such as Ethereum. The system was evaluated through comprehensive experiments on performance and security. Performance results show a throughput of up to 60.86 transactions per second and an average latency of 3.40 s under a load of 10,000 transactions. Security validation confirmed resistance against digital signature forgery, invalid smart contracts, race conditions, and double-spending attacks. Despite the promising performance, several limitations remain. The current system was developed and tested on a single machine as a simulation-based study using transaction logs without integration of real smart meters or actual energy tokenization in real-time scenarios. In future work, we will focus on integrating real-time smart meters and implementing full energy tokenization to achieve a complete and autonomous smart grid platform. Overall, the proposed system significantly enhances data integrity, trust, and resistance to counterfeiting in smart grids. Full article

This paper studies a supply chain comprising a supplier, a third-party remanufacturer (TPR), and a retailer. The retailer sells both genuine and remanufactured products (i.e., Model O). Leveraging information advantages, the retailer may engage in brand deception by mislabeling remanufactured products as genuine to obtain extra profits (i.e., Model BD). AI-powered anti-counterfeiting technologies (AIT) (i.e., Model BA) and revenue-sharing contracts (i.e., Model C) are considered countermeasures. The findings reveal that (1) brand deception reduces (increases) sales of genuine (remanufactured) products, prompting the supplier (TPR) to lower (raise) wholesale prices. The asymmetric profit erosion effect highlights the gradual erosion of profits for the supplier, retailer, and TPR under brand deception. (2) The bi-interval adaptation effect indicates that AIT is particularly effective in industries with low adaptation resistance. When both the relabeling rate and industry adaptation resistance are low (high), Model BA (Model O) achieves a triple win. (3) Sequentially, when the industry adaptation resistance is low, AIT can significantly improve total profits, consumer surplus (CS), and social welfare (SW). Compared to Model BD, revenue-sharing offers slight advantages in CS but notable disadvantages in SW. Full article

Malaria primarily affects developing nations and is one of the most destructive and pervasive tropical parasite infections. Antimalarial drug resistance, characterized by a parasite’s ability to survive and reproduce despite recommended medication doses, poses a significant challenge. Along with resistance to antimalarial drugs, the rate of mutation a parasite undergoes, overall parasite load, drug potency, adherence to treatment, dosing accuracy, drug bioavailability, and the presence of poor-quality counterfeit drugs are some of the contributing factors that elicit opposition to treatment. The ubiquitin-proteasome system (UPS) has become a promising drug target for malaria because of its central importance in the parasite’s life cycle and its contribution to artemisinin resistance. Polymorphisms in the Kelch13 gene of Plasmodium falciparum are the best-known markers for artemisinin resistance and are associated with a highly active UPS. Certain proteasome inhibitors, which are the other key players of the UPS, have demonstrated activity against malarial parasites and the ability to work with artemisinin. This work describes how, through targeting the UPS, the greater effectiveness of antimalarial drugs—especially where there is strong resistance—can be achieved, which contributes to overcoming the drug resistance phenomenon in malaria. Full article

Reversible optical regulation has potential applications in optical anti-counterfeiting, storage, and catalysis. Compared to common power materials, the reverse opal structure has a larger specific surface area and an increased contact area for optical regulation, which is expected to achieve higher regulation rates. However, it is difficult to achieve reversible and repeatable regulation of the luminescent properties of photonic crystals, especially with the current research on the structural collapse of photonic crystals. In this work, WO₃: Yb³⁺, Er³⁺ inverse photonic crystals were prepared by the template approach, and reversible multi-mode optical modification was investigated. Upon heat treatment in a reducing atmosphere or air, the color of the photonic crystals can reversibly change from light yellow to dark green, accompanied by changes in absorption and upconversion of luminescence intensity. The stability and fatigue resistance of this reversible optical modification ability were explored through cyclic experiments, providing potential practical applications for photocatalysis, optical information storage, and electrochromism. Full article

Micro/nano photonic barcoding has emerged as a promising technology for information security and anti-counterfeiting applications owing to its high security and robust tamper resistance. However, the practical application of conventional micro/nano photonic barcodes is constrained by limitations in encoding capacity and identification verification (e.g., broad emission bandwidth and the expense of pulsed lasers). Herein, we propose high-capacity photonic barcode labels by leveraging continuous-wave (CW) pumped monolayer tungsten disulfide (WS₂) lasing. Large-area, high-quality monolayer WS₂ films were grown via a vapor deposition method and coupled with external cavities to construct optically pumped microlasers, thus achieving an excellent CW-pumped lasing with a narrow linewidth (~0.39 nm) and a low threshold (~400 W cm⁻²) at room temperature. Each pixel within the photonic barcode labels consists of closely packed WS₂ microlasers of varying sizes, demonstrating high-density and nonuniform multiple-mode lasing signals that facilitate barcode encoding. Notably, CW operation and narrow-linewidth lasing emission could significantly simplify detection. As proof of concept, a 20-pixel label exhibits a high encoding capacity (2.35 × 10¹⁰⁸). This work may promote the advancement of two-dimensional materials micro/nanolasers and offer a promising platform for information encoding and security applications. Full article

The worsening of antibiotic resistance is a multifactorial process. One aspect of this is the counterfeiting of antibiotic medications. This is supposed to be particularly high in developing countries, including Nigeria. Therefore, the potency of some antibiotic drugs dispensed in community pharmacies in Gwale, Kano, Nigeria, was investigated in this case study. Three products, each from different manufacturers, with the active ingredients of ceftriaxone, gentamicin, ciprofloxacin, and metronidazole, respectively, were included in this study. By means of a disc-diffusion assay, the effect against the typed strains Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) as well as Clostridium tetani isolated from soil was tested. Clinical isolates of S. aureus and E. coli were also used. While antibiotics, with the exception of ciprofloxacin-containing preparations against C. tetani, showed acceptable efficacy against the typed strains by comparison with the clinical science laboratory references, a predominant failure was observed with the clinical isolates. Thus, the investigated drug preparations can be considered of acceptable quality for the treatment of susceptible bacterial infections. This excludes counterfeits in the sampled preparations. However, the insufficient efficacy against clinical isolates further documents the severity of nosocomial bacteria. Full article

Blockchain-based applications necessitate the authentication of connected devices if they are employed as blockchain oracles. Alongside identity authentication, it is crucial to ensure resistance against tampering, including safeguarding against unauthorized alterations and protection against device counterfeiting or cloning. However, attaining these functionalities becomes more challenging when dealing with resource-constrained devices like low-cost IoT devices. The resources of IoT devices depend on the capabilities of the microcontroller they are built around. Low-cost devices utilize microcontrollers with limited computational power, small memory capacity, and lack advanced features such as a dedicated secure cryptographic chip. This paper proposes a method employing a Physical Unclonable Function (PUF) to authenticate identity and tamper resistance in IoT devices. The suggested PUF relies on a microcontroller’s internal pull-up resistor values and, in conjunction with the microcontroller’s built-in analog comparator, can also be utilized for device self-checking. A main contribution of this paper is the proposed PUF method which calculates the PUF value as the average value of many single PUF measurements, resulting in a significant increase in accuracy. The proposed PUF has been implemented successfully in a low-cost microcontroller device. Test results demonstrate that the device, specifically the microcontroller chip, can be identified with high accuracy (99.98%), and the proposed PUF method exhibits resistance against probing attempts. Full article